feat: Publish-Remote Gate und die Anleitung fuer eine private Instanz (2.2.0)

Files changed:
- .gitignore
- AGENTS.md
- CHANGES.md
- VERSION
- instructions/gates.md
- instructions/private-instance.md
- tools/chemenu/commands/doctor.py
- tools/chemenu/commands/git_publish.py
- tools/chemenu/config.py
- tools/chemenu/tests/test_git_publish.py

tools/chemenu/tests/test_git_publish.py

@@ -1,3 +1,4 @@
+import json
 import subprocess
 
 import pytest
@@ -905,3 +906,115 @@ def test_numstat_survives_a_non_ascii_filename(repo):
     change = next(c for c in collect_changes([]) if c.path == name)
     assert change.status == "modified"
     assert (change.added, change.removed) == (1, 2)
+
+
+# --- Publish-Remote Gate -----------------------------------------------------
+
+
+def _allowlist(root, *urls):
+    (root / config.PUBLISH_REMOTES_FILENAME).write_text(
+        json.dumps({"schema": 1, "allowed_push_urls": list(urls)}), encoding="utf-8"
+    )
+
+
+def test_no_allowlist_means_unrestricted(repo):
+    """Absence is a legitimate state: a checkout with nothing private in it
+    should not have to declare anything to publish at all."""
+    assert git_publish.read_allowed_push_urls() is None
+    assert git_publish.publish_remote_refusal("origin", "main") is None
+
+
+def test_allowed_url_passes_the_gate(repo):
+    _allowlist(repo, git_publish.push_url_for("origin"))
+    assert git_publish.publish_remote_refusal("origin", "main") is None
+
+
+def test_gate_refuses_a_remote_not_on_the_list(repo):
+    _git(repo, "remote", "add", "upstream", "https://example.com/public.git")
+    _allowlist(repo, git_publish.push_url_for("origin"))
+    refusal = git_publish.publish_remote_refusal("upstream", "main")
+    assert refusal is not None
+    assert "https://example.com/public.git" in refusal
+    assert "Nothing was committed or pushed" in refusal
+
+
+def test_gate_matches_the_url_not_the_remote_name(repo):
+    """A name-based list would pass a repointed `origin`, which is the failure
+    this gate exists to catch."""
+    _allowlist(repo, "ssh://git@example.com/only-this.git")
+    assert git_publish.publish_remote_refusal("origin", "main") is not None
+
+
+def test_gate_reads_pushurl_when_the_remote_sets_one(repo):
+    """`git push` writes to `pushurl` when present, so that is the value that
+    has to be checked - not the fetch URL beside it."""
+    _git(repo, "remote", "set-url", "--push", "origin", "https://example.com/elsewhere.git")
+    _allowlist(repo, "https://example.com/elsewhere.git")
+    assert git_publish.push_url_for("origin") == "https://example.com/elsewhere.git"
+    assert git_publish.publish_remote_refusal("origin", "main") is None
+
+
+def test_gate_refuses_when_the_fetch_url_is_listed_but_the_pushurl_is_not(repo):
+    fetch_url = git_publish.push_url_for("origin")
+    _git(repo, "remote", "set-url", "--push", "origin", "https://example.com/elsewhere.git")
+    _allowlist(repo, fetch_url)
+    assert git_publish.publish_remote_refusal("origin", "main") is not None
+
+
+def test_publish_exits_42_and_commits_nothing_when_the_remote_is_refused(repo):
+    _git(repo, "remote", "add", "upstream", "https://example.com/public.git")
+    _allowlist(repo, git_publish.push_url_for("origin"))
+    before = _git(repo, "rev-parse", "HEAD").stdout.strip()
+    (repo / "kb" / "secret.md").write_text("private\n", encoding="utf-8")
+
+    with pytest.raises(typer.Exit) as excinfo:
+        _publish(remote="upstream")
+    assert excinfo.value.exit_code == EXIT_NEEDS_CLEARANCE
+
+    # Nothing committed, and the file is still sitting there unstaged - the
+    # refusal message promises both. (`git status --porcelain` collapses the
+    # wholly-untracked `kb/` to one entry, so check the index directly.)
+    assert _git(repo, "rev-parse", "HEAD").stdout.strip() == before
+    assert (repo / "kb" / "secret.md").exists()
+    assert "secret.md" not in _git(repo, "ls-files").stdout
+
+
+def test_no_push_skips_the_gate(repo):
+    """`--no-push` publishes nowhere, so there is no wrong target to protect
+    against - and a local commit must stay possible."""
+    _allowlist(repo, "ssh://git@example.com/only-this.git")
+    (repo / "kb" / "page.md").write_text("local\n", encoding="utf-8")
+    _publish(push=False)
+    assert "page.md" in _git(repo, "show", "--name-only", "HEAD").stdout
+
+
+def test_unreadable_allowlist_fails_instead_of_falling_open(repo):
+    """A broken file must not be read as 'no restriction' - that would turn a
+    corrupted safeguard into a silently disabled one."""
+    (repo / config.PUBLISH_REMOTES_FILENAME).write_text("{not json", encoding="utf-8")
+    with pytest.raises(typer.Exit):
+        git_publish.read_allowed_push_urls()
+
+
+def test_allowlist_without_a_usable_list_fails(repo):
+    (repo / config.PUBLISH_REMOTES_FILENAME).write_text(
+        json.dumps({"schema": 1, "allowed_push_urls": "not-a-list"}), encoding="utf-8"
+    )
+    with pytest.raises(typer.Exit):
+        git_publish.read_allowed_push_urls()
+
+
+def test_empty_allowlist_refuses_everything(repo):
+    """An empty list is a deliberate 'publish nowhere', not an oversight that
+    should behave like an absent file."""
+    _allowlist(repo)
+    assert git_publish.publish_remote_refusal("origin", "main") is not None
+
+
+def test_gate_has_no_flag_that_opens_it(repo):
+    """The other two gates clear with a token; this one deliberately does not,
+    because the right fix is a deliberate edit by the user."""
+    import inspect
+
+    params = inspect.signature(publish_command).parameters
+    assert not any("remote" in name and "confirm" in name for name in params)